Pemrograman VisualMinggu …2… Page 1 MINGGU Ke Dua Pemrograman Visual Pokok Bahasan: Console...

Minggu …2…

Pemrograman Visual

MINGGU Ke Dua

Pemrograman VisualPemrograman Visual

Pokok Bahasan:Console Application

Tujuan Instruksional Khusus:Mahasiswa dapat menjelaskan dan mengaplikasikan console apllication, tipe data, operator aritmatika, relational operator dan message dialogs

Referensi:Deitel Deitel, Visual Basic 2008 (2009), How to Program, Prentice Hall. Chapter 3

Pemrograman Visual Minggu …2…

Agenda• Displaying line of text

• Creating console application

• Adding Integer

• Memory concepts

• Arithmetic

• Equality and Relational operator

• Message Dialog to display message


Displaying Line of Text


Module Module1

Sub Main() Console.WriteLine("Wellcome to Visual Basic .NET") Console.ReadKey() End Sub

End Module

• Perbedaan Write dengan WriteLine• Fungsi ReadKey()

Displaying Line of Text (Continued …)


Creating a Console Application


IDE with an open console application


Renaming the program files in the properties windows


Setting the Startup Object


Writing Code and Using IntelliSense


Parameter Info Window


Running the program from the command prompt


Syntax Error Indicated by the IDE


Adding Integer


Adding Integer (Continued …)


• The ReadLine method cause the program to pause and wait for user input, once the user presses the enter key, the input is returned to the program and execution resumes

• A Syntax error indicates a violation of visual basic’s rule for creating

Adding Integer Summary


Primitive Types


Memory Concepts

• Variable names, such as number1, number2, total, correspond to locations in the computer’s memory

• Each variable has a name, type, size and value• Whenever a value is placed in a memory location,

it replaces the value previously stored in that location. The Previous value is destroyed

• When a value is read from a memory location, the process is nondestructive, meaning that the value in a memory is not changed


Memory locations after an addition operation


Arithmetic Operator


Precedence of Arithmetic Operator


Example Precedence of Arithmetic Operator


Summary Arithmetic• Binary operators operate on two operands; unary operator

operate on one operand.• The Mod operator yields the remainder after division.• Arithmetic expressions in visual basic must be written in

straight-line form to enter programs into a computer.• Parentheses are used in visual basic expressions in the

same manner as in algebraic expressions.• Visual basic applies the operators in arithmetic expressions

in a precise sequence, which is determine by the rule of the operator precedence

• If an expression contains multiple operator with the same precedence, the order in which the operators are applied is determined by their associability. In VB, all binary operators associate from left to right.


Equality and Operational Operators


Comparison with equality and relational operators


Summary Equality and Operational Operators• Visual Basic’s If… Then statement allows a

program to make a decision based on the truth or falsity of a condition . If the condition is true, the statement in the body of the If… Then statement executes. If the condition is false, the body statement does not execute.

• Conditions in If… Then statements can be formed by using the equality operators and relational operators. Equality operators and relational operators are also called comparison operators.

• Relational and equality operators have the same level of precedence and associate from left to right


Message dialog to display message


Message dialog to display message (Continued …)

• Visual Basic provides class MessageBox for creating message dialogs

• Line 10 calls the Sqrt method of the Math class to compute the square root of 2. The value returned is a floating-point number, so we declare the variable root as type Double.

• Note the use of spacing in lines 13–14 of Fig. 3.28. To improve readability, long statements may be split over several lines using the line-continuation character , _ . Line 13 uses the line-continuation character to indicate that line 14 is a continuation of the pre-ceding line.

• Lines 13–14 (Fig. 3.28) call method Show of class MessageBox. This method takes a comma-separated argument list. The first argument is the string that is displayed in the message dialog. The second argument is the string that is displayed in the message dialog’s title bar.


Analyzing the MessageBox


Summary Message dialog to display message

• Message dialogs are windows that display messages to the user. Visual Basic provides the class MessageBox for creating message dialogs.

• The .NET Framework Class Library organizes groups of related classes into namespaces.

• The System.Windows.Forms namespace contains windows-related classes (i.e., forms and dialogs) that help you define graphical user interfaces (GUIs) for their applications.

• GUI components facilitate data entry by the user and the formatting and presenting of data outputs to the user.

• An Imports statement indicates that a program uses the features provided by a specific namespace, such as System.Windows.Forms.

• To improve readability, long statements may be split over several lines with the line-continuation character ( _ ). Although a single statement can contain as many line-continuation characters as necessary, at least one whitespace character must precede each line-continuation character.

• Assemblies that contain compiled classes for reuse in applications are located in files with a .dll (dynamic link library) extension.


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